From 8590eb48308a9cebdfec4606935341f235bd9cb0 Mon Sep 17 00:00:00 2001
From: Debadree Chatterjee <debadree333@gmail.com>
Date: Tue, 7 Feb 2023 23:13:57 +0530
Subject: [PATCH] lib: add aborted() utility function

Fixes: https://github.com/nodejs/node/issues/37220
Refs: https://github.com/nodejs/node/pull/36607
PR-URL: https://github.com/nodejs/node/pull/46494
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
---
 doc/api/util.md                    | 45 +++++++++++++++++++++++
 lib/internal/abort_controller.js   | 34 ++++++++++++++---
 lib/util.js                        |  3 ++
 test/parallel/test-aborted-util.js | 59 ++++++++++++++++++++++++++++++
 4 files changed, 136 insertions(+), 5 deletions(-)
 create mode 100644 test/parallel/test-aborted-util.js

diff --git a/doc/api/util.md b/doc/api/util.md
index 71d3a9f32eae47..7318b0e3f76fdc 100644
--- a/doc/api/util.md
+++ b/doc/api/util.md
@@ -1983,6 +1983,51 @@ const channel = new MessageChannel();
 channel.port2.postMessage(signal, [signal]);
 ```
 
+## `util.aborted(signal, resource)`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+> Stability: 1 - Experimental
+
+* `signal` {AbortSignal}
+* `resource` {Object} Any non-null entity, reference to which is held weakly.
+* Returns: {Promise}
+
+Listens to abort event on the provided `signal` and
+returns a promise that is fulfilled when the `signal` is
+aborted. If the passed `resource` is garbage collected before the `signal` is
+aborted, the returned promise shall remain pending indefinitely.
+
+```cjs
+const { aborted } = require('node:util');
+
+const dependent = obtainSomethingAbortable();
+
+aborted(dependent.signal, dependent).then(() => {
+  // Do something when dependent is aborted.
+});
+
+dependent.on('event', () => {
+  dependent.abort();
+});
+```
+
+```mjs
+import { aborted } from 'node:util';
+
+const dependent = obtainSomethingAbortable();
+
+aborted(dependent.signal, dependent).then(() => {
+  // Do something when dependent is aborted.
+});
+
+dependent.on('event', () => {
+  dependent.abort();
+});
+```
+
 ## `util.types`
 
 <!-- YAML
diff --git a/lib/internal/abort_controller.js b/lib/internal/abort_controller.js
index 7a4381ecd13cb3..6fec167ffc86c1 100644
--- a/lib/internal/abort_controller.js
+++ b/lib/internal/abort_controller.js
@@ -8,6 +8,7 @@ const {
   ObjectDefineProperties,
   ObjectSetPrototypeOf,
   ObjectDefineProperty,
+  PromiseResolve,
   SafeFinalizationRegistry,
   SafeSet,
   Symbol,
@@ -22,11 +23,13 @@ const {
   kTrustEvent,
   kNewListener,
   kRemoveListener,
+  kWeakHandler,
 } = require('internal/event_target');
 const {
+  createDeferredPromise,
   customInspectSymbol,
-  kEnumerableProperty,
   kEmptyObject,
+  kEnumerableProperty,
 } = require('internal/util');
 const { inspect } = require('internal/util/inspect');
 const {
@@ -38,6 +41,8 @@ const {
 } = require('internal/errors');
 
 const {
+  validateAbortSignal,
+  validateObject,
   validateUint32,
 } = require('internal/validators');
 
@@ -94,7 +99,7 @@ function customInspect(self, obj, depth, options) {
   return `${self.constructor.name} ${inspect(obj, opts)}`;
 }
 
-function validateAbortSignal(obj) {
+function validateThisAbortSignal(obj) {
   if (obj?.[kAborted] === undefined)
     throw new ERR_INVALID_THIS('AbortSignal');
 }
@@ -132,7 +137,7 @@ class AbortSignal extends EventTarget {
    * @type {boolean}
    */
   get aborted() {
-    validateAbortSignal(this);
+    validateThisAbortSignal(this);
     return !!this[kAborted];
   }
 
@@ -140,7 +145,7 @@ class AbortSignal extends EventTarget {
    * @type {any}
    */
   get reason() {
-    validateAbortSignal(this);
+    validateThisAbortSignal(this);
     return this[kReason];
   }
 
@@ -202,7 +207,7 @@ class AbortSignal extends EventTarget {
   }
 
   [kTransfer]() {
-    validateAbortSignal(this);
+    validateThisAbortSignal(this);
     const aborted = this.aborted;
     if (aborted) {
       const reason = this.reason;
@@ -357,6 +362,24 @@ function transferableAbortController() {
   return AbortController[kMakeTransferable]();
 }
 
+/**
+ * @param {AbortSignal} signal
+ * @param {any} resource
+ * @returns {Promise<void>}
+ */
+async function aborted(signal, resource) {
+  if (signal === undefined) {
+    throw new ERR_INVALID_ARG_TYPE('signal', 'AbortSignal', signal);
+  }
+  validateAbortSignal(signal, 'signal');
+  validateObject(resource, 'resource', { nullable: false, allowFunction: true, allowArray: true });
+  if (signal.aborted)
+    return PromiseResolve();
+  const abortPromise = createDeferredPromise();
+  signal.addEventListener('abort', abortPromise.resolve, { [kWeakHandler]: resource, once: true });
+  return abortPromise.promise;
+}
+
 ObjectDefineProperties(AbortController.prototype, {
   signal: kEnumerableProperty,
   abort: kEnumerableProperty,
@@ -375,6 +398,7 @@ module.exports = {
   AbortController,
   AbortSignal,
   ClonedAbortSignal,
+  aborted,
   transferableAbortSignal,
   transferableAbortController,
 };
diff --git a/lib/util.js b/lib/util.js
index 893a085c90aa3b..4ee13a28f58512 100644
--- a/lib/util.js
+++ b/lib/util.js
@@ -393,6 +393,9 @@ module.exports = {
   get transferableAbortController() {
     return lazyAbortController().transferableAbortController;
   },
+  get aborted() {
+    return lazyAbortController().aborted;
+  },
   types
 };
 
diff --git a/test/parallel/test-aborted-util.js b/test/parallel/test-aborted-util.js
new file mode 100644
index 00000000000000..7991d72cb6c62f
--- /dev/null
+++ b/test/parallel/test-aborted-util.js
@@ -0,0 +1,59 @@
+// Flags: --expose-gc
+'use strict';
+
+const common = require('../common');
+const { aborted } = require('util');
+const assert = require('assert');
+const { getEventListeners } = require('events');
+const { spawn } = require('child_process');
+
+{
+  // Test aborted works when provided a resource
+  const ac = new AbortController();
+  aborted(ac.signal, {}).then(common.mustCall());
+  ac.abort();
+  assert.strictEqual(ac.signal.aborted, true);
+  assert.strictEqual(getEventListeners(ac.signal, 'abort').length, 0);
+}
+
+{
+  // Test aborted with gc cleanup
+  const ac = new AbortController();
+  aborted(ac.signal, {}).then(common.mustNotCall());
+  setImmediate(() => {
+    global.gc();
+    ac.abort();
+    assert.strictEqual(ac.signal.aborted, true);
+    assert.strictEqual(getEventListeners(ac.signal, 'abort').length, 0);
+  });
+}
+
+{
+  // Fails with error if not provided abort signal
+  Promise.all([{}, null, undefined, Symbol(), [], 1, 0, 1n, true, false, 'a', () => {}].map((sig) =>
+    assert.rejects(aborted(sig, {}), {
+      code: 'ERR_INVALID_ARG_TYPE',
+    })
+  )).then(common.mustCall());
+}
+
+{
+  // Fails if not provided a resource
+  const ac = new AbortController();
+  Promise.all([null, undefined, 0, 1, 0n, 1n, Symbol(), '', 'a'].map((resource) =>
+    assert.rejects(aborted(ac.signal, resource), {
+      code: 'ERR_INVALID_ARG_TYPE',
+    })
+  )).then(common.mustCall());
+}
+
+{
+  const childProcess = spawn(process.execPath, ['--input-type=module']);
+  childProcess.on('exit', common.mustCall((code) => {
+    assert.strictEqual(code, 13);
+  }));
+  childProcess.stdin.end(`
+    import { aborted } from 'node:util';
+    await aborted(new AbortController().signal, {});
+  `);
+}